1. Field of the Invention
The present invention relates to a crawler traveling apparatus, more particularly to a crawler traveling apparatus mounted in e.g. a rear section of a tractor.
2. Description of the Related Art
A semi-crawler tractor having a crawler type traveling apparatus as a “rear wheel” of the tractor, instead of a rear tired wheel is known from e. Japanese Patent Application “Kokai” No. 2008-168876. In this crawler traveling apparatus, a tack frame is pivotally supported via a pivot shaft to a rear axle case of a traveling machine body. At front and rear ends of this track frame, there are mounted front and rear driven wheels and at intermediate positions thereof, there are mounted front and rear free wheels. Upwardly of a front/rear intermediate position of the track frame, there is mounted a drive wheel which receives drive force from a rear axle supported to the rear axle case. Of the free wheels, the rear free wheels are pivoted to an equalizer link and a front/rear intermediate portion of this equalizer link is pivoted to the track frame 2 via a pivot shaft.
With such crawler traveling apparatus as described above, the upper face of the track frame is formed as a flat face. So, when an amount of earth, sand etc, adhering to the inner peripheral surface of the crawler may be raised in association with traveling of the crawler and then drop onto the upper face of the track frame to be eventually accumulated thereon. Especially, if a pair of right and left driven wheels are mounted across the rear end of the track frame, accumulation of sand, earth or the like may occur on the upper face of the track frame between the right and left driven wheels, thus making its removal difficult.
Further, with this conventional crawler traveling apparatus, as the track frame is formed narrower than the wheel rolling face of the crawler, the sand, earth or the like stuck to the inner peripheral face of the crawler may be raised in association with traveling of the crawler and then be placed directly on the wheel rolling face or it may be first accumulated on the upper face of the track frame and then become entrapped between the wheels and the wheel rolling face in the course of the circulatory movement of the crawler.